nacos注册发现原理

 注册发现流程

1. 客户端将ip,端口号,命名空间等封装成instance;
2. 客户端定时发送instance给服务端;
3. 服务端接收请求,判断instance是否已经存在;
4. 服务端判断已存在刷新心跳;
5. 服务端判断instance不存在则存进注册表中,一个set集合;

 客户端

注册自身服务

nacos客户端监听了启动事件,调用start()方法,封装注册信息成instance对象(ip,port,weight,group,namspace...),用nacosRestTemplate发送rest请求到服务端

spring.factories

​ 监听事件

​

start()方法

​ 将instance放到map中去
​

 发送rest请求

​

 服务端接口地址
​

 与官网手册的注册接口一致 

​

服务端

查找接口/nacos/v1/ns/instance 的post方法

​

​创建service 时,里边有一个双层map,就是隔离命名空间,group的数据结构

 /**
  * Map(namespace, Map(group::serviceName, Service)).
  */
private final Map> serviceMap = new ConcurrentHashMap<>();

​

​

/*
 * Copyright 1999-2018 Alibaba Group Holding Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.alibaba.nacos.naming.consistency.ephemeral.distro;

import com.alibaba.nacos.api.common.Constants;
import com.alibaba.nacos.api.exception.NacosException;
import com.alibaba.nacos.consistency.DataOperation;
import com.alibaba.nacos.core.distributed.distro.DistroConfig;
import com.alibaba.nacos.core.distributed.distro.DistroProtocol;
import com.alibaba.nacos.core.distributed.distro.component.DistroDataProcessor;
import com.alibaba.nacos.core.distributed.distro.entity.DistroData;
import com.alibaba.nacos.core.distributed.distro.entity.DistroKey;
import com.alibaba.nacos.naming.cluster.ServerStatus;
import com.alibaba.nacos.naming.cluster.transport.Serializer;
import com.alibaba.nacos.naming.consistency.Datum;
import com.alibaba.nacos.naming.consistency.KeyBuilder;
import com.alibaba.nacos.naming.consistency.RecordListener;
import com.alibaba.nacos.naming.consistency.ephemeral.EphemeralConsistencyService;
import com.alibaba.nacos.naming.consistency.ephemeral.distro.combined.DistroHttpCombinedKey;
import com.alibaba.nacos.naming.core.DistroMapper;
import com.alibaba.nacos.naming.core.Instances;
import com.alibaba.nacos.naming.core.Service;
import com.alibaba.nacos.naming.core.v2.upgrade.UpgradeJudgement;
import com.alibaba.nacos.naming.misc.GlobalConfig;
import com.alibaba.nacos.naming.misc.GlobalExecutor;
import com.alibaba.nacos.naming.misc.Loggers;
import com.alibaba.nacos.naming.misc.SwitchDomain;
import com.alibaba.nacos.naming.pojo.Record;
import com.alibaba.nacos.sys.utils.ApplicationUtils;
import com.alibaba.nacos.common.utils.StringUtils;
import org.javatuples.Pair;
import org.springframework.context.annotation.DependsOn;

import javax.annotation.PostConstruct;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;


@DependsOn("ProtocolManager")
@org.springframework.stereotype.Service("distroConsistencyService")
public class DistroConsistencyServiceImpl implements EphemeralConsistencyService, DistroDataProcessor {
    
    private static final String ON_RECEIVE_CHECKSUMS_PROCESSING_TAG = "1";
    
    private final DistroMapper distroMapper;
    
    private final DataStore dataStore;
    
    private final Serializer serializer;
    
    private final SwitchDomain switchDomain;
    
    private final GlobalConfig globalConfig;
    
    private final DistroProtocol distroProtocol;
    
    private volatile Notifier notifier = new Notifier();
    
    private Map> listeners = new ConcurrentHashMap<>();
    
    private Map syncChecksumTasks = new ConcurrentHashMap<>(16);
    
    public DistroConsistencyServiceImpl(DistroMapper distroMapper, DataStore dataStore, Serializer serializer,
            SwitchDomain switchDomain, GlobalConfig globalConfig, DistroProtocol distroProtocol) {
        this.distroMapper = distroMapper;
        this.dataStore = dataStore;
        this.serializer = serializer;
        this.switchDomain = switchDomain;
        this.globalConfig = globalConfig;
        this.distroProtocol = distroProtocol;
    }
    
    //初始化加载
    @PostConstruct
    public void init() {
        GlobalExecutor.submitDistroNotifyTask(notifier);
    }
    
    @Override
    public void put(String key, Record value) throws NacosException {
        //单机注册
        onPut(key, value);
        // If upgrade to 2.0.X, do not sync for v1.
        if (ApplicationUtils.getBean(UpgradeJudgement.class).isUseGrpcFeatures()) {
            return;
        }
        distroProtocol.sync(new DistroKey(key, KeyBuilder.INSTANCE_LIST_KEY_PREFIX), DataOperation.CHANGE,
                DistroConfig.getInstance().getSyncDelayMillis());
    }
    
    @Override
    public void remove(String key) throws NacosException {
        onRemove(key);
        listeners.remove(key);
    }
    
    @Override
    public Datum get(String key) throws NacosException {
        return dataStore.get(key);
    }
    
    /**
     * Put a new record.
     *
     * @param key   key of record
     * @param value record
     */
    public void onPut(String key, Record value) {
        
        if (KeyBuilder.matchEphemeralInstanceListKey(key)) {
            Datum datum = new Datum<>();
            datum.value = (Instances) value;
            datum.key = key;
            datum.timestamp.incrementAndGet();
            dataStore.put(key, datum);
        }
        
        if (!listeners.containsKey(key)) {
            return;
        }
        
        //丢进阻塞队列中去
        notifier.addTask(key, DataOperation.CHANGE);
    }

    
  
    
    public boolean isInitialized() {
        return distroProtocol.isInitialized() || !globalConfig.isDataWarmup();
    }
    
    public class Notifier implements Runnable {
        
        private ConcurrentHashMap services = new ConcurrentHashMap<>(10 * 1024);
        
        private BlockingQueue> tasks = new ArrayBlockingQueue<>(1024 * 1024);
        
        /**
         * Add new notify task to queue.
         *
         * @param datumKey data key
         * @param action   action for data
         */
        public void addTask(String datumKey, DataOperation action) {
            
            if (services.containsKey(datumKey) && action == DataOperation.CHANGE) {
                return;
            }
            if (action == DataOperation.CHANGE) {
                services.put(datumKey, StringUtils.EMPTY);
            }
            tasks.offer(Pair.with(datumKey, action));
        }
        
        public int getTaskSize() {
            return tasks.size();
        }
        
        @Override
        public void run() {
            Loggers.DISTRO.info("distro notifier started");
            
            for (; ; ) {
                try {
                    Pair pair = tasks.take();
                    // 注册流程
                    handle(pair);
                } catch (Throwable e) {
                    Loggers.DISTRO.error("[NACOS-DISTRO] Error while handling notifying task", e);
                }
            }
        }
        
        //注册核心流程
        private void handle(Pair pair) {
            try {
                String datumKey = pair.getValue0();
                DataOperation action = pair.getValue1();
                
                services.remove(datumKey);
                
                int count = 0;
                
                if (!listeners.containsKey(datumKey)) {
                    return;
                }
                
                for (RecordListener listener : listeners.get(datumKey)) {
                    
                    count++;
                    
                    try {
                        if (action == DataOperation.CHANGE) {
                            //注册核心流程
                            listener.onChange(datumKey, dataStore.get(datumKey).value);
                            continue;
                        }
                        
                        if (action == DataOperation.DELETE) {
                            listener.onDelete(datumKey);
                            continue;
                        }
                    } catch (Throwable e) {
                        Loggers.DISTRO.error("[NACOS-DISTRO] error while notifying listener of key: {}", datumKey, e);
                    }
                }
                
                if (Loggers.DISTRO.isDebugEnabled()) {
                    Loggers.DISTRO
                            .debug("[NACOS-DISTRO] datum change notified, key: {}, listener count: {}, action: {}",
                                    datumKey, count, action.name());
                }
            } catch (Throwable e) {
                Loggers.DISTRO.error("[NACOS-DISTRO] Error while handling notifying task", e);
            }
        }
    }
}

 listener.onChange(datumKey, dataStore.get(datumKey).value);方法里边调用到写时复制方法public void updateIps(List ips, boolean ephemeral);

 //写时复制代码
    public void updateIps(List ips, boolean ephemeral) {
        
        //是不是临时节点,是复制ephemeralInstances一份出来,ephemeralInstances是nacos所有临时节点
        Set toUpdateInstances = ephemeral ? ephemeralInstances : persistentInstances;
        
       //写入代码...
        
        //复制代码
        if (ephemeral) {
            ephemeralInstances = toUpdateInstances;
        } else {
            persistentInstances = toUpdateInstances;
        }
    }